Spring 单例和多例模式@Scope("prototype")注解使用

最新推荐文章于 2025-10-17 07:30:15 发布

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本文通过示例展示了Spring框架中Bean的默认作用域为单例，并介绍了如何配置Bean为多例模式。通过测试代码对比了单例和多例模式下Bean实例的差异。

Spring中默认生成的bean是全局的而且将只有一个实例,测试代码如下:

@Configuration
public class GlobalConfig {
    @Bean
    public ThreadPoolTaskExecutor defaultThreadPool(){
        ThreadPoolTaskExecutor executor=new ThreadPoolTaskExecutor();
        executor.setCorePoolSize(16);
        executor.setMaxPoolSize(64);
        executor.setQueueCapacity(16);
        executor.setThreadNamePrefix("test");
        executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
        executor.setKeepAliveSeconds(60);
        executor.initialize();
        return  executor;
    }
}

@RunWith(SpringRunner.class)
@SpringBootTest
public class CachedemoApplicationTests {

    //    引入对应的对象内容
    @Resource(name = "defaultThreadPool")
    private ThreadPoolTaskExecutor executor;

    @Resource(name = "defaultThreadPool")
    private ThreadPoolTaskExecutor executor1;


    @Before
    public void test1() {

        System.out.println(executor1.toString());
    }

    @Test
    public void test() {
        System.out.println(executor.toString());
    }
}

返回结果:

org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor@11e355ca
org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor@11e355ca

如果要时的Spring开启多例模式,要增加

@Configuration
public class GlobalConfig {
    @Bean
    @Scope("prototype")
    public ThreadPoolTaskExecutor defaultThreadPool(){
        ThreadPoolTaskExecutor executor=new ThreadPoolTaskExecutor();
        executor.setCorePoolSize(16);
        executor.setMaxPoolSize(64);
        executor.setQueueCapacity(16);
        executor.setThreadNamePrefix("test");
        executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
        executor.setKeepAliveSeconds(60);
        executor.initialize();
        return  executor;
    }
}

返回结果:

org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor@43984213
org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor@2ff7a7